I have a Frigidaire s/s less than 2 years old and the refrigerator section stops cooling, but the freezer section continues blowing cold air inside it for a while longer then it stops. If I unplug it for 24 hours it will start working again for about a week, then stops working again.
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=FRS6LF7JB0
Here is the tech sheet
http://manuals.frigidaire.com/prodinfo_pdf/Anderson/240389629.pdf
When this happens does the compressor run all the time, if yes then you may have a defrost problem.
When it happens again remove the evaporator cover in the freezer so you can see the coils.
If they are heavily iced/frosted over to the point where the evaporator fan cannot pull air through them you have a defrost problem.
Do not let them de-ice.
If yes.
Manually force a defrost cycle (see the tech sheet). The fans and compressor turn off when in defrost.
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the defrost board (Item 23 in Section 2) needs replacing.
If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 14 in Section 9) from the wiring and measure it for continuity, usually around 50 ohms or so.
Yours looks like it may be as high as 90 ohms.
If the heater is OK
Remove one wire to the defrost thermostat (Item 21 in Section 9) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.
If both the above are OK then odds are the defrost board is toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.